Nearly 5,000 Veterans undergo abdominal aortic aneurysm (AAA) repair each year in VA hospitals. Randomized trials, including the VA-based Open Versus Endovascular Repair (OVER) Trial, have found endovascular AAA repair (EVAR), is associated with lower perioperative morbidity and mortality, less pain, and shorter length of stay than open surgical repair (OSR) However, OSR is more durable, has fewer long-term complications such as late rupture, and Veterans treated with EVAR and OSR have similar survival within two years following surgery. Given these tradeoffs, controversy remains as to which method is best suited for an individual Veteran who AAA repair, and preliminary analyses needs have found broad variations across VA hospitals in how Veterans are treated for AAA. Treatment decisions for AAA need to be aligned with Veterans' preferences. For example, a Veteran for whom a rapid recovery is of primary importance and long-term durability a lesser concern has a treatment preference which aligns most closely with EVAR. Similarly, a Veteran who wishes to avoid repeated follow-up visits and late re-interventions has a treatment preference that aligns most closely with OSR. However, while AAA treatment type varies across VA hospitals, it is unknown if these treatment variations occurs as a result of Veterans preferences, or independent of Veterans' preferences. Surgeon preferences for repair type have been poorly described, especially for surgeons treating Veterans. In preliminary work, we have performed observational analyses, surveys, and cognitive interviews. This works has demonstrated variation in AAA repair type in VA and refined qualitative methods to better understand Veterans' and surgeons? treatment decisions. In this proposal, in a cohort of Veterans who are candidates for either repair type (OSR or EVAR), we will use a survey explore Veterans' knowledge and preferences for AAA repair, and determine if Veterans who receive a decision aid as well as the survey are more likely to receive their treatment choice. We describe a cluster-randomized trial comparing two ways to better align Veterans' preferences and treatments for AAA: (1) a validated decision aid describing AAA repair types with a survey measuring Veterans' preference for repair type -- versus (2) the survey alone. Enrolled Veterans will be candidates for either endovascular or open repair, and be followed at VA hospitals by vascular surgery teams who regularly perform both types of repair. In Aim 1, we will determine Veterans' preferences for endovascular or open repair and identify domains associated with each repair type. In Aim 2, we will compare agreement between Veterans' preferences and repair type between the decision aid+survey and survey-alone groups. We will identify factors associated with agreement. Our findings will be reported to the National Surgery Office Vascular Surgery Advisory Board to help ensure Veterans' preferences remain at the center of AAA treatment decisions. We have recruited 20 VA Medical Centers and their vascular surgery teams who are anxious to participate in this important trial to help Veterans make the best decisions.